Hydrogen cooled hydride storage unit

ABSTRACT

A hydrogen gas cooled hydrogen storage element which includes a hydrogen storage alloy material in which hydrogen flow channels are provided. The flow channels provide pathways through the hydrogen storage material to allow for high speed hydrogen gas flow. A portion of the high speed hydrogen flow is stored within the storage material which releases its heat of hydride formation. The remainder of the hydrogen flows through the hydrogen storage material at a sufficient mass flow rate to remove the heat of hydride formation.

RELATED APPLICATION INFORMATION

[0001] This application is a continuation of U.S. application Ser. No.09/465,904, filed Dec. 17, 1999.

FIELD OF THE INVENTION

[0002] The instant invention relates generally to hydrogen storage unitsand more specifically to hydrogen gas cooled storage units. The storageunit includes corrugation through which excess high flow rate hydrogenflows, thereby transferring the heat of hydride formation from thestorage material to the excess hydrogen and removing it from the storageunit.

BACKGROUND OF THE INVENTION

[0003] The instant patent application for the first time, describes ahydrogen storage unit useful for a hydrogen-based economy. The storageunit allows for fast and efficient cooling and/or heating thereof usinggaseous hydrogen as a direct, convective heat transfer medium. Theinstant storage element makes it possible to efficiently andeconomically transfer heat between subsystems of a completeinfrastructure system. Such an infrastructure system (from “source towheel”), is the subject of copending U.S. application Ser. No.09/444,810, entitled “A Hydrogen-based Ecosystem” filed on Nov. 22, 1999for Ovshinsky, et al. (the '810 application), which is herebyincorporated by reference. This infrastructure, in turn, is madepossible by hydrogen storage alloys that have surmounted the chemical,physical, electronic and catalytic barriers that have heretofore beenconsidered insoluble. These alloys are fully described in copending U.S.patent application Ser. No. 09/435,497, entitled “High Storage CapacityAlloys Enabling a Hydrogen-based Ecosystem”, filed on Nov. 6, 1999 forOvshinsky et al. (“the '497 application”), which is hereby incorporatedby reference. The '497 application relates generally and specifically toalloys which solve the, up to now, unanswered problem of havingsufficient hydrogen storage capacity with exceptionally fast kinetics topermit the safe and efficient storage of hydrogen to provide fuel for ahydrogen based economy, such as powering internal combustion engine andfuel cell vehicles. In the '497 application the inventors for the firsttime disclosed the production of Mg-based alloys having both hydrogenstorage capacities higher than about 6 wt. % and extraordinary kinetics.This revolutionary breakthrough was made possible by considering thematerials as a system and thereby utilizing chemical modifiers and theprinciples of disorder and local order, pioneered by Stanford R.Ovshinsky, in such a way as to provide the necessary catalytic localorder environments, such as surfaces and at the same time designing bulkcharacteristics for storage and high rate charge/discharge cycling. Inother words, these principles allowed for tailoring of the material bycontrolling the particle and grain size, topology, surface states,catalytic activity, microstructure, and total interactive environmentsfor storage capacity.

[0004] The combination of the '810 and the '497 applications solves thetwin basic barriers which have held back the use of the “ultimate fuel,”namely hydrogen storage capacity and a hydrogen infrastructure. With theuse of the alloys of the '497 application, hydrogen can be shippedsafely by boats, barges, trains, trucks, etc. when in solid form.However, the infrastructure of the '810 application requires thermalmanagement and efficient heat utilization throughout the entire system.The instant invention makes the necessary heat transfer between thesubsystems of the infrastructure simple, efficient, and economic.

[0005] As the world's population expands and its economy increases, theatmospheric concentrations of carbon dioxide are warming the earthcausing climate change. However, the global energy system is movingsteadily away from the carbon-rich fuels whose combustion produces theharmful gas. Experts say atmospheric levels of carbon dioxide may bedouble that of the pre-industrial era by the end of the next century,but they also say the levels would be much higher except for a trendtoward lower-carbon fuels that has been going on for more than 100years. Furthermore, fossil fuels cause pollution and are a causativefactor in the strategic military struggles between nations. Furthermore,fluctuating energy costs are a source of economic instability worldwideFor nearly a century and a half, fuels with high amounts of carbon haveprogressively been replaced by those containing less. First wood, whichis high in carbon, was eclipsed in the late 19^(th) century by coal,which contains less carbon. Then oil, with a lower carbon content still,replace coal in the 1960's. Now analysts say that natural gas, lighterstill in carbon, may be entering its heyday, and that the day ofhydrogen—providing a fuel with no carbon at all—may at last be about todawn. As a result, experts estimate the world's economy today burns lessthan two-thirds as much carbon per unit of energy produced as it did in1860, despite the fact that carbon based fuels are still being used bythe automotive industry.

[0006] In the United States, it is estimated, that the trend towardlower-carbon fuels combined with greater energy efficiency has, since1950, reduced by about half the amount of carbon spewed out for eachunit of economic production. Thus, the decarbonization of the energysystem is the single most important fact to emerge from the last 20years of analysis of the system. It had been predicted that thisevolution will produce a carbon-free energy system by the end of the21^(st) century. The instant invention helps to shorten that period to amatter of years. In the near term, hydrogen will be used in fuel cellsfor cars, trucks and industrial plants, just as it already providespower for orbiting spacecraft. But ultimately, hydrogen will alsoprovide a general carbon-free fuel to cover all fuel needs.

[0007] As noted in recent newspaper articles, large industries,especially in America, have long been suspicious of claims that theglobe is warming and have vociferously negated the science of climatechange. Electric utilities, among others, initially took the positionthat international treaties on climate change would cut economic growthand cost jobs. A dramatic shift has now occurred, in which the problemsare finally being acknowledged and efforts are at last being undertakento solve them. Therefore, it is very encouraging that some of theworld's biggest companies, such as Royal Dutch/Shell and BP Amoco, twolarge European oil firms, now state plainly what was once consideredheresy: global warming is real and merits immediate action. A number ofAmerican utilities have vowed to find ways to reduce the harm done tothe atmosphere by their power plants. DuPont, the world's biggestchemical firm, has even declared that it will voluntarily reduce itsemissions of greenhouse gases to 35% of their level in 1990 within adecade. The automotive industry, which is a substantial contributor toemissions of greenhouse gases and other pollutants (despite itsvehicular specific reductions in emissions), has now realized thatchange is necessary as evidenced by their electric and hybrid vehicles.In this field, the assignee of the subject invention, has developed theOvonic nickel metal hydride battery, the enabling battery makingelectric and hybrid vehicles possible.

[0008]FIG. 1, taken from reliable industrial sources, is a graphdemonstrating society's move toward a carbon-free environment as afunction of time starting with the use of wood in the early 1800s andending in about 2010 with the beginning of a “hydrogen” economy. In the1800s, fuel was primarily wood in which the ratio of hydrogen to carbonwas about 0.1. As society switched to the use of coal and oil, the ratioof hydrogen to carbon increased first to 1.3 and then to 2. Currently,society is inching closer to the use of methane in which the hydrogen tocarbon ratio is further increased to 4 (methane has serious problemswith safety, cost and infrastructure). However, the ultimate goal forsociety is to employ a carbon-free fuel, i.e., the most ubiquitous ofelements, pure hydrogen. The obstacle has been the lack of solid statestorage capacity and infrastructure. The inventors of the '497 and the'810 applications have made this possible by inventing a 7% storagematerial (7% is an umoptimized fugure and will be increased along withbetter kinetics) with exceptional absorption/desorption kinetics, i.e.at least 80% charge in less than 2 minutes and an infrastructure to usethese storage alloys. These alloys allow for the first time, a safe,high capacity means of storing, transporting and delivering purehydrogen.

[0009] Hydrogen is the “ultimate fuel.” It is inexhaustible and isconsidered by most to be “THE” fuel for the next millennium. Hydrogen isthe most plentiful element in the universe (over 95% of all matter) andwas the first element created by the “Big-Bang.” Hydrogen can provide aclean source of energy for our planet which can be produced by variousprocesses which split water into hydrogen and oxygen and the hydrogencan be stored and transported in solid state form. For example,economical, lightweight, triple-junction amorphous silicon solar cellssolar cells (an invention pioneered by Stanford R. Ovshinsky) such asthose set forth in U.S. Pat. No. 4,678,679, (the disclosure of which isincorporated herein by reference) can be readily disposed adjacent abody of water, where their inherently high open circuit voltage can beused to dissociate water into its constituent gases, and the hydrogen soproduced can be collected. These high efficiency, lightweight solarpanels can also be place on nearby farms, in water, or on land. It isnotable that the photovoltaic process for dissociating water to formhydrogen can be a step toward solving the problems of water purificationthroughout the world. Electricity can be generated to transport and pumpthe hydrogen into metal hydride storage beds that include the highstorage capacity, lightweight metal hydride alloys. The ultra-highcapacities of the alloys of the '497 application allow this hydrogen tobe stored in solid form and transported by barge, tanker, train or truckin safe, economical form for ultimate use. Energy is the basic necessityof life and civilization for any society today and the use of hydrogenin the manner described herein as the basic source of energy wouldminimize the likelihood of wars fought for control of fossil fuels.Instead of “from well to wheel,” the phrase now recited will be “fromsource to wheel.”

[0010] In the past considerable attention has been given to the use ofhydrogen as a fuel or fuel supplement. While the world's oil reservesare depletable, the supply of hydrogen remains virtually unlimited.While hydrogen can be produced from coal, natural gas and otherhydrocarbons, it is preferable to form hydrogen by the electrolysis ofwater, preferably via energy from the sun which is composed mainly ofhydrogen and can, itself, be thought of as a giant hydrogen “furnace”.However, hydrogen can also be produced by the electrolysis of waterusing any other form of economical energy (e.g., wind, waves,geothermal, hydroelectric, nuclear, etc.) Furthermore, hydrogen, is aninherently low cost fuel. Hydrogen has the highest density of energy perunit weight of any chemical fuel and is essentially non-polluting sincethe main by-product of “burning” hydrogen is water. Thus, hydrogen canbe a means of solving many of the world's energy related problems, suchas climate change, pollution, strategic dependancy on oil, etc., as wellas providing a means of helping developing nations.

[0011] While hydrogen has wide potential application as a fuel, a majordrawback in its utilization, especially in mobile uses such as thepowering of vehicles, has been the lack of an acceptable lightweighthydrogen storage medium. Storage of hydrogen as a compressed gasinvolves the use of large and heavy vessels. Thus, as shown in FIG. 2,compressed hydrogen at 5000 psi only has a hydrogen density of 31g/liter. Additionally, large and very expensive compressors are requiredto store hydrogen as a compressed gas and compressed hydrogen gas is avery great explosion/fire hazzard.

[0012] Hydrogen also can be stored as a liquid. Storage as a liquid,however, presents a serious safety problem when used as a fuel for motorvehicles since hydrogen is extremely flammable. Liquid hydrogen alsomust be kept extremely cold, below −253° C., and is highly volatile ifspilled. Moreover, liquid hydrogen is expensive to produce and theenergy necessary for the liquefaction process is a major fraction of theenergy that can be generated by burning the hydrogen. Another drawbackto storage as a liquid is the costly losses of hydrogen due toevaporation, which can be as high as 5% per day. Also, the storagedensity of liquid hydrogen, as shown in FIG. 2 is only 71 g/liter.

[0013] For the first time, storage of hydrogen as a solid hydride, usingthe atomically engineered alloys of the '497 application can provide agreater percent weight storage than storage as a compressed gas or aliquid in pressure tanks. Also, hydrogen storage in a solid hydride issafe and does not present any of the hazard problems that hydrogenstored in containers as a gas or a liquid does, because hydrogen, whenstored in a solid hydride form, exists in it's lowest free energy state.As shown, again in FIG. 2, storage of hydrogen in a 7% Ovonic thermalhydrogen storage alloy provides a hydrogen density of 103 g/liter, morethan 3 times the density of compressed hydrogen gas.

[0014] In addition to the problems associated with storage of gaseous orliquid hydrogen, there are also problems associated with the transportof hydrogen in such forms. For instance transport of liquid hydrogenwill require super-insulated tanks, which will be heavy and bulky andwill be susceptible to rupturing and explosion. Also, a portion of theliquid hydrogen will be required to remain in the tanks at all times toavoid heating-up and cooling down of the tank which would incur bigthermal losses. As for gaseous hydrogen transportation, pressurizedtankers could be used for smaller quantities of hydrogen, but these toowill be susceptible to rupturing and explosion. For larger quantities, awhole new hydrogen pipeline transportation system would need to beconstructed or the compressor stations, valves and gaskets of theexisting pipeline systems for natural gas will have to be adapted andretrofitted to hydrogen use. This assumes, of course, that theconstruction material of these existing pipelines will be suited tohydrogen transportation.

[0015] The instant invention is useful in the infrastructure system ofthe '810 application. When hydrogen is transferred into a storage bed,heat is liberated when the hydrogen and metallic material reacts to formthe hydrides. This heat must be removed to allow the hydriding reactionsto proceed to completion. Conversely, heat is absorbed during thedecomposition of the hydride to release hydrogen, and the hydrides arepreferably heated during their decomposition to provide an adequate rateof liberation of hydrogen therefrom.

[0016] In the past, heating and cooling of the metallic hydride materialhas been accomplished by conventional techniques including heating orcooling the container in which the material is held, or spacing tubesthroughout the bed of hydride material and circulating a heat exchangemedium in the tubes. In such techniques, the amount of heat transferredto the metallic hydride depends on the area of the container or thesurface area of the tubes extending through the bed, as well as on theconductive heat transfer characteristics of the metallic hydride. It hasalso been suggested to use hydrogen gas itself as a convective energycarrier, and, thus, overcome the limitations of the above-mentionedtechniques. In addition, the direct cooling and heating of the hydridespermits rapid cycling between charge and discharge operations, and,thus, increase the efficiency of a given system. As proposed in papernumber 760569 presented at the SAE Fuels and Lubricants Meeting in St.Louis, Mo., Jun. 7-10, 1976, by Hoffman et al. of Brookhaven NationalLaboratory, hydrogen would be circulated through the metallic hydride inthe containers to carry heat directly to where it is needed. Heatexchange would take place with the hydrogen in an external heatexchanger to supply the heat to the hydrogen. This technique is alsoused in U.S. Pat. No. 4,185,979 issued Jan. 29, 1980 to Woolley.However, even though direct convective hydrogen cooling of the thermalhydrogen storage beds is well known in the art, no one had designed oroptimized the hydrogen storage units for this type of cooling, thusthere is a need for such an optimized hydrogen storage unit in the art.

SUMMARY OF THE INVENTION

[0017] The instant invention provides for a hydrogen gas cooled hydrogenstorage element which includes a hydrogen storage alloy material inwhich hydrogen flow channels are provided. The flow channels providepathways through the hydrogen storage material to allow for high speedhydrogen gas flow. A portion of the high speed hydrogen flow is storedwithin the storage material which releases its heat of hydrideformation. The remainder of the hydrogen flows through the hydrogenstorage material at a sufficient mass flow rate to remove the heat ofhydride formation.

[0018] The hydrogen storage alloy material powder is formed into a beltof hydrogen storage material by compaction and/or sintering and mayinclude a support means. The support means is typically at least oneselected from the group consisting of mesh, grid, matte, foil, foam andplate and is formed from a metal selected from the group consisting ofNi, Al, Cu, Fe and mixtures or alloys thereof. The storage alloy powderphysically bonded to the support means, if any, is then spirally woundinto a coil. Hydrogen flow channels are provided within the coil byeither corrugating at least one surface of the belt of hydrogen storagealloy material or by interleaving a corrugated material or a foam, mesh,matte or even expanded metal sheet within the spirals of the coil. Thecorrugated material or foam, mesh, matte or expanded metal sheet can beformed form metals or thermally conductive non-metals.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a graph having time plotted on the abscissa and the H/Cratio plotted on the ordinate, said graph demonstrating the movement ofsociety toward carbon-free sources of fuel;

[0020]FIG. 2 is a graphical bar-chart of hydrogen storage density ingiliter for hydrogen stored as a compressed hydrogen, liquid hydrogen,and a 7% Ovonic solid hydride storage material;

[0021]FIG. 3, is a plot of hydrogen storage versus time at 300° C. for acompressed hydrogen storage pellet of a Mg-based alloy useful in thestorage units of the instant invention;

[0022]FIG. 4 is a partial cut-away schematic depiction of a hydrogenstorage unit according to the instant invention;

[0023]FIG. 5 is a schematic depiction of a hydrogen storage unitaccording to the instant invention which includes multiple storage coilsin a single casing;

[0024]FIG. 6 is a schematic depiction of a hydrogen storage bed whichincludes the hydrogen storage units according to the instant invention;

[0025]FIG. 7 is a stylistic depiction of a hydrogen refueling station;

[0026]FIG. 8 shows a schematic representation of a hydrogen gas supplysystem for powering an internal combustion engine vehicle; and

[0027]FIG. 9 shows a schematic representation of a hydrogen gas supplysystem for powering for a fuel cell vehicle.

DETAILED DESCRIPTION OF THE INVENTION

[0028] Computer modeled analysis of the cooling requirement for hydrogenstorage units when being charged at a very high rate have shown that ifthe hydrogen storage alloy material is formed into an annular tube, witha central cooling channel through which hydrogen is flown at high rates,the limit to the thickness of the annulus is about 2 mm. That is,computer modeling indicates that the maximum distance from the coolingchannel within the annular member will be 2 mm for proper cooling uponcharge. However, it has also been determined by this computer modelingthat, using the units of the instant invention, none of the hydrogenstorage materials will ever be more than 1 mm from a cooling channel.

[0029] In order to provide for a hydrogen storage unit which isconvectively cooled by high flow rate hydrogen, the unit requires thatthe storage material allow for high rate hydrogen flow therethrough.Thus, rather than just flowing the coolant gas, hydrogen, over theexterior surface of the storage unit, or a single internal surface of anannular storage material, hydrogen needs to flow at a high rate directlythrough the hydrogen storage material in coolant channels. Therefore,the storage material will need flow channels through it to allow for thehigh flow rate of the hydrogen coolant. Also, since high speed gas isflowing through the storage material, the material needs to be compactedand restrained from entraining into the hydrogen flow. The storage unitof the instant invention allows for high speed hydrogen flow through thestorage material, thus allowing for efficient convective heating andcooling, while avoiding entrainment of the compacted/sintered storagealloy.

[0030] Any alloy which safely and efficiently stores and releaseshydrogen may be used in the storage unit of the instant invention.Specifically useful are alloys such as Ti-Zr based AB₂ room temperaturehydrogen storage alloys and high capacity Mg-based storage alloys. Mostuseful are the high capacity, high kinetics storage alloys of the '497application. In general the alloys contain greater than about 90 weight% magnesium, and contain at least one modifier element. The at least onemodifier element creates a magnesium based alloy which is capable ofstoring at least 6.9 weight % hydrogen and is capable of absorbing 80%of the full storage capacity of hydrogen in under 1.5 minutes at 300° C.The modifier elements mainly include Ni and Mm (misch metal) and canalso include additional elements such as Al, Y and Si. Thus the alloyswill typically contain 0.52-2.5 weight % nickel and about 1.0-4.0 weight% Mm (predominantly contains Ce and La and Pr). The alloy may alsocontain one or more of 3-7 weight % Al, 0.1-1.5 weight % Y and 0.3-1.5weight % silicon. An example of the absorption kinetics of such asmagnesium based alloy which has been formed into a pellet is shown inFIG. 3, in which the hydrogen storage versus time is plotted. As can beseen, the material is capable of storing more than 6.5 weight % hydrogenand absorbs 6.5 weight % in 1.4 minutes at 300° C. This is excellentcapacity and kinetics indeed.

[0031]FIG. 4 is a partial cut-away view of the hydrogen cooled storageunit of the instant invention. The unit specifically includes a casing1, which houses the storage coil 2, which is composed of a spirallywound hydrogen storage alloy belt 3 interleaved with a sheet of flowchannel material 4 which allows for flow of the high flow rate hydrogenthrough the storage unit.

[0032] The hydrogen storage alloy belt 3 includes a hydrogen storagealloy which may be bonded to a support means. The support means may beformed from a variety of materials with the appropriate thermodynamiccharacteristics that can help to provide heat transfer into and out ofsaid hydrogen storage alloy. The useful materials for the support meansinclude both metals and non-metals. Preferable metals include those fromthe group consisting of Ni, Al, Cu, Fe and mixtures or alloys thereof.Examples of support means that can be formed from metals include wiremesh, expanded metal and foamed metal. This support material may, storehydrogen, which may improve the overall performance of the storage unit.

[0033] The hydrogen storage alloy material may be physically bonded tothe support means by compaction and/or sintering processes. The alloymaterial is first converted into a fine powder. The powder is thencompacted, optionally onto the support means, to form a belt of storagematerial. The compaction process causes the powder to adhere to itselfand, if included, become an integral part of the support means. Aftercompaction, the belt including any support means that has beenimpregnated with alloy powder is preheated and then sintered. Thepreheating process liberates excess moisture and discourages oxidationof the alloy powder. Sintering is carried out in a high temperature,substantially inert atmosphere containing hydrogen. The temperature issufficiently high to promote particle-to-particle bonding of the alloymaterial as well as the bonding of the alloy material to any supportmeans.

[0034] The hydrogen storage alloy belt is then spirally wound into acoil along with along interleaved sheet of flow channel material 4 whichprovides the hydrogen flow channels for the high flow rate hydrogen. Theflow channel material 4 is formed from a thermally conductive sheet ofmaterial which very highly porous and thus allows for high speed flow ofhydrogen through the unit. The flow channel material may be formed frompolymers or metals or even thermally conductive non-metals. Examples ofpolymers would be corrugated polypropylene sheet porouspolytetrafluoroethylene sheet. Metals, if used would be in the form of acorrugated metal sheet, expanded metal, or metal foam, matte or mesh.The metal may be capable of storing hydrogen also, thereby enhancing theoverall storage capacity of the system. Useful metals include Cu, Ni andAl and mixtures or alloys thereof. Useful non-metals can includethermally conductive ceramics and thermally conductive graphitematerials. The non-metals may be in the form of corrugated sheet, foam,matte or mesh of non-metals fibers, etc. Once again, the non-metal mayalso store hydrogen, thereby enhancing the storage capacity of thesystem. It should be noted that the hydrogen storage alloy belts 3 andthe flow channel sheets 4 may be interleaved in any proportion desiredto provide adequate cooling to the storage alloy. That is, it may bedesirable to include many hydrogen storage belt layers per flow channellayer in the final product, or visa-versa. As an alternative to spirallywinding a separate flow channel material 4 into the coil 2, the belt ofstorage material 3 may be corrugated on one or both surfaces thereofbefore coiling, thus providing in-situ corrugation.

[0035] Compacting and sintering the alloy material onto a support meansincreases the packing density of the alloy material, thereby improvingthe thermodynamic and kinetic characteristics of the hydrogen storagesystem. The close contact between the support means and the alloymaterial improves the efficiency of the heat transfer into and out ofthe hydrogen storage alloy material as hydrogen is absorbed anddesorbed. In addition, the uniform distribution of the storagealloy/support means throughout the interior of the container providesfor an even temperature and heat distribution throughout the bed ofalloy material. This results in a more uniform rates of hydrogenabsorption and desorption throughout the entirety thereof, thus creatinga more efficient energy storage system.

[0036] One problem when using just alloy powder (without a supportmeans) in hydrogen storage beds is that of self-compaction due toparticle size reduction. That is, during repeated hydriding anddehydriding cycles, the alloy materials expand and contract as theyabsorb and desorb hydrogen. Some alloy materials have been found toexpand and contract by as much as 25% in volume as a result of hydrogenintroduction into and release from the material lattice. As a result ofthe dimensional change in the alloy materials, they crack, undergofracturing and break up into finer and finer particles. After repeatedcycling, the fine particles self-compact causing inefficient hydrogentransfer as well as high stresses that are directed against the walls ofthe storage container. Also, within the present system, the particles ofthe storage material may be entrained into the high flow rate gasstream, and be carried out of the storage unit.

[0037] However, the processes used to attach the alloy material onto thesupport means keeps the alloy particles firmly bonded to each other aswell as to the support means during the absorption and desorptioncycling. Furthermore, the tight packaging of the support means withinthe container serves as a mechanical support that keeps the alloyparticles in place during the expansion, contraction and fracturing ofthe material.

[0038] The coils 2 may be of any axial length and diameter, as requiredby the end use. However, the economics costs and physicalcapability/practicality of production machinery must be taken intoaccount. Coils produced by the instant inventors are typically 2-5inches in axial length and 1-4 inches in diameter. The coils can have acentral annular opening if desired, but this is not necessary. Thecentral annular opening can be used to insert combustive or electricheaters if desired to assist in release of the hydrogen, if needed forthe end use applications.

[0039] Once the coils are manufactured, adding capacity to any hydrogenstorage unit is as simple as packing multiple coils into a single ormultiple casings. As shown in FIG. 5, many coils 2 can be placed intoone casing 1 to form a storage unit 5. This allows for easy, economicmanufacture of the coils themselves, but also allows for large capacitystorage systems by combining many coils into one system.

[0040] Once the multiple coils 2 are inserted into a casing 1 to form aunit 5, multiple units can be bundled into a complete storage bed. FIG.6 shows how multiple units 5 can be packed into an outer shell 6 to formsuch a bed 9 (hydrogen inlet and outlet ports and manifolds are notshown). This bed 9 can also be cooled/heated external to the casings ofthe individual units through ports 7 and 8. The external heating/coolingcan accomplished via hydrogen gas or other useful gaseous or liquid heattransfer media. It should be noted that while a specific bed 9 shape anddesign are depicted, one of ordinary skill in the art could modify theseparameters and still be within the spirit and scope of the instantinvention.

[0041]FIG. 7 is a stylistic depiction of a hydrogen refueling stationwhich specifically shows how hydrogen is used to capture the heat ofhydride formation in the vehicles storage bed 9 and transfer that heatto the stations primary hydride storage bed 10 to assist in the releaseof hydrogen from the primary storage bed. Specifically, high flow ratehydrogen is dispensed from the “pump” 13 into the vehicle's hydrogenstorage bed 9 through cool hydrogen supply line 11 a. Some of thehydrogen is absorbed into the hydrogen storage material with in the bed,thereby releasing heat of hydride formation. This heat is removed by theexcess cool hydrogen. The now heated hydrogen leaves storage bed 9 andis transported to the pump 13 via hot hydrogen return line 12 a. The hothydrogen is then transported from the pump 13 to the stations primaryhydrogen storage bed 10 via hot hydrogen return line 12 b. The hothydrogen releases its heat into the hydrogen storage material within bed10 to assist in providing the required heat (heat of dehydriding) torelease the stored hydrogen therein. The released hydrogen, now cooler,is supplied to the pump 13, via cool hydrogen supply line 11 b, toultimately be sent again to the vehicles hydrogen storage bed 9. Thisset up allows for very fast charging of a vehicles storage bed 9, andyet eliminates waste of the released heat and overheating of the bed.

Hydrogen Powered Internal Combustion Engine and Fuel Cell Vehicles

[0042] The instant storage unit is useful as a hydrogen supply for manyapplications. One such application is the field of automobiles.Specifically, the storage unit can be used as a source of hydrogen forinternal combustion engine (ICE) or fuel cell (FC) vehicles.

[0043]FIG. 8 shows a schematic representation of a hydrogen gas supplysystem for an ICE vehicle, which is for supplying a hydrogen engine 21with hydrogen gas. The system has a hydrogen gas storage bed 9 and anengine waste heat transfer supply passage 23 which leads engine wasteheat (in the form of exhaust gas or engine coolant) discharged from theengine 21 to the hydrogen gas storage bed 9. The system also includes areturn passage 24 for returning any engine coolant used to heat thehydrogen storage material back to the engine 21 and an exhaust gas vent27 for releasing used exhaust gas. The system further includes ahydrogen gas supply passage 25 which leads hydrogen gas from thehydrogen gas storage bed 9 to the engine 21. The engine waste heattransfer supply passage 23 is provided with a temperature regulatingunit 26 which regulates the temperature of the waste heat to beintroduced into the hydrogen gas storage bed 9. With such a system,waste heat generated within the ICE can be efficiently used to heat thehydrogen storage material to release hydrogen therefrom for use in theICE.

[0044]FIG. 9 shows a schematic representation of a hydrogen gas supplysystem for an FC vehicle, which is for supplying a fuel cell 28 withhydrogen gas. The system has a hydrogen gas storage bed 9 and a fuelcell waste heat/hydrogen transfer supply passage 29 which leads fuelcell waste heat and unused hydrogen discharged from the fuel cell 28 toa hydrogen gas combustor 30. Waste heat from the fuel cell may be in theform of heated gases or heated aqueous electrolyte. The hydrogencombustor 30, heats a thermal transfer medium (preferably in the form ofthe aqueous electrolyte from the fuel cell) utilizing waste heat fromthe fuel cell 28, and by combusting hydrogen. Hydrogen is supplied tothe combustor 30 via unused hydrogen from the fuel cell 28, and viafresh hydrogen supplied from the hydrogen storage bed 9 via hydrogensupply line 34. Heated thermal transfer medium is supplied to thehydrogen storage bed 9 via supply line 33. The system also includes areturn passage 36 for returning any fuel cell aqueous electrolyte usedto heat the hydrogen storage material back to the fuel cell 28 and anexhaust gas vent 35 for releasing used combustor gas. The system furtherincludes a hydrogen gas supply passage 31 which leads hydrogen gas fromthe hydrogen gas storage bed 9 to the fuel cell 28.

[0045] While the invention has been described in connection withpreferred embodiments and procedures, it is to be understood that it isnot intended to limit the invention to the described embodiments andprocedures. On the contrary it is intended to cover all alternatives,modifications and equivalence which may be included within the spiritand scope of the invention as defined by the claims appendedhereinafter.

We claim:
 1. A hydrogen gas cooled hydrogen storage element comprising:a hydrogen storage alloy; and hydrogen flow channels provided withinsaid hydrogen storage material, said flow channels providing pathwaysthrough said hydrogen storage material; said pathways allowing for highspeed hydrogen gas flow therethrough such that a portion of saidhydrogen gas flow is stored within said hydrogen storage materialthereby releasing heat and the remainder of said hydrogen gas flowremoves said heat from said hydrogen storage alloy.
 2. The hydrogen gascooled hydrogen storage element of claim 1 , wherein said hydrogenstorage alloy is a belt of compacted powered alloy.
 3. The hydrogen gascooled hydrogen storage element of claim 2 , wherein said hydrogenstorage alloy is a belt of compacted powered alloy physically bonded toa support means.
 4. The hydrogen gas cooled hydrogen storage element ofclaim 3 , wherein said hydrogen storage alloy is physically bonded tosaid support means by compaction and/or sintering.
 5. The hydrogen gascooled hydrogen storage element of claim 3 , wherein said support meanscomprises at least one selected from the group consisting of mesh, grid,matte, foil, foam and plate.
 6. The hydrogen gas cooled hydrogen storageelement of claim 3 , wherein said support means is formed from a metal.7. The hydrogen gas cooled hydrogen storage element of claim 6 , whereinsaid support means is formed from one or more metals selected from thegroup consisting of Ni, Al, Cu, Fe and mixtures or alloys thereof. 8.The hydrogen gas cooled hydrogen storage element of claim 2 , whereinbelt of compacted powered alloy is spirally wound into a coil.
 9. Thehydrogen gas cooled hydrogen storage element of claim 8 , wherein saidhydrogen flow channels are provided by corrugating at least one surfaceof said belt before it is spirally wound into a coil.
 10. The hydrogengas cooled hydrogen storage element of claim 8 , wherein said hydrogenflow channels are provided by interleaving a flow channel materialwithin said spirally wound coil.
 11. The hydrogen gas cooled hydrogenstorage element of claim 10 , wherein said flow channel material is acorrugated polymer sheet.
 12. The hydrogen gas cooled hydrogen storageelement of claim 11 , wherein said corrugated polymer sheet is acorrugated polypropylene sheet.
 13. The hydrogen gas cooled hydrogenstorage element of claim 11 , wherein said corrugated polymer sheet is acorrugated polytetrafluoroethylene sheet.
 14. The hydrogen gas cooledhydrogen storage element of claim 9 , wherein said flow channel materialis a corrugated metal sheet.
 15. The hydrogen gas cooled hydrogenstorage element of claim 14 , wherein said corrugated metal sheet isformed from at least one metal selected from Ni, Al, Cu, and mixtures oralloys thereof.
 16. The hydrogen gas cooled hydrogen storage element ofclaim 10 , wherein said flow channel material is a metal foam sheet. 17.The hydrogen gas cooled hydrogen storage element of claim 10 , whereinsaid flow channel material is a metal mesh sheet.
 18. The hydrogen gascooled hydrogen storage element of claim 10 , wherein said flow channelmaterial is a metal matte sheet.
 19. The hydrogen gas cooled hydrogenstorage element of claim 10 , wherein said flow channel material is agraphite foam sheet.
 20. The hydrogen gas cooled hydrogen storageelement of claim 10 , wherein said flow channel material is a graphitemesh sheet.
 21. The hydrogen gas cooled hydrogen storage element ofclaim 10 , wherein said flow channel material is a graphite matte sheet.